Arylaminomethyl thiazyl sulphides



Patented Aug. 6, 1935 ARYLAMINOME'rHyr.

THIAZYL `SULPHIDES Clyde Coleman, Passaic, N. J., assignr, by mesne assignments,

to United States Rubber Company,

New York, NrY., a corporation ofNew Jersey No Drawing.

Application September 5, 1931, Serial N0. 561,502 y This invention relates to the preparation of a new class of chemical compounds and to the resulting products.

It has been found that by interacting a hier captothiazole, a primary aromatic amine,` and formaldehyde, under conditions precluding the elimination of hydrogen sulphide, a new class of chemical compounds is obtained. The following probable general formula is assigned to the new compounds which are referred to as arylaminomethyl thiazyl sulphide: R1-S-CH2--NH-R wherein R is a substituted or unsubsttuted aryl group and R1 is a thiazyl group, for example, a benzothiazyl group. The benzothiazyl group is shown by the following structure, in which the atoms are numbered for the purposesof this invention as indicated:

Among the mercaptothiazoles which may be reacted with the primary aromaticarnine .and formaldehyde are the mercaptoarylthiazoles, such as l-mercaptobenzothiazole, .and horno# logues and substitution products thereof, for instance l-mercaptotcluthiazole (sometimes referred to as l-mercaptotolylthiazole), l-mercap- `to5nitrobenzothiazole, l-mercapto-Li-nitrobenzothiazole, lmercapto5 chlorobenzothiazole, 1- mercapto-5-ethoxybenzothiazole, 1-mercapto-4- chlorobenzothiazole. K The new compounds may be prepared asy illustrated in the following examples: p

Example A.-Reaction product of mercaptobenzothiazole, formaldehyde, and ortho-toluidinr having the probable formula:

\S/ l CH3 428 grams (4 mois) of ortho-toluidine areclissolved inv about l liter of toluene,.and 468 grams (4 mols) of mercaptobenzothiazole are added to the toluene solution of ortho-toluidine thus ob-f tained, and the whole mass is thoroughly agitated, the mercaptobenzcthiazole remaining largely in suspension. An aqueous solution of formaldehyde of about SiS-40% strength containing 4 mols of formaldehye is then added with agitation, and cooling if necessary. A reaction between the ortho-toluidine, formaldehyde, Aand the mercaptobenzothiazole takes place` quickly atroom temperature, and the new product separates as a fine nearly white crystalline solid of a high degree of purity. Theproduct is recovered'fromfthe supernatant liquidfand( freed` of solvent. "In'he melting point is about 145 146 C. vThe amount recoveredinthisway isabout 960 grams (about -83% of theoretical yield). The remaining 17% remansfdissolved in the toluene and may be recoveredin` any suitable wayV to give a substantially.l00% yield.

Example BReacti0n product of mercapto- Abenzothiazole, formaldehyde,V and para-toluidine having the `probable formula` 107 grams (one mol.) of para-toluidine are dis,- Solved in about V500 cc. of alcohol, and l167 grams of mercaptobenzothlazole are then added and the mixture isthoroughly agitated. An Vaqueous solution of 38440% of formaldehyde containing one mol; offormaldehyde is then added. The new product',Vv whichfis the reaction'product of paratoluidine',l formaldehyde, and mercaptobenzothiazoie, separates from the alcohol as a yellowishwhite crystallinr-. solid, and 'is recovered as in the Y previous' example.4 TheA product thus obtained weighs about 195' grains."` The' melting point is about `10'7" C. which is'raised to 11G- 111 C. by recrystallizing the product from alcohol. About grams of the product remain in solution and may berecovered'by any suitable means therefrom; itisi identlcalwith the rst fraction isolated. i l" Example (Ty-Reaction product of mercaptobenzothlazole, "formaldehyde and aniline having the probable formula ferri@ l 65 .grams of aniline (0.5 mol.) and 83.5 grams of mercaptobenzothiazole (0.5 mol.) are added to 300 ,cc. of valcohol themercaptobenzothiazole remains,largely-insuspension while the aniline is completely dissolved, no reaction occurring between the two materials. Then an amount of formaldehyde solution 4ofabout 38% strength containing 15 grams `(0.75 mol.) of formaldehyde is'addedland the mixture is agitated. ,The temperature of thereaction mixture rises to about 30 VC. As the reaction proceeds,the contents of the begin to assume a lighter color and after about 10-15 minutes the reaction is complete. The reaction` mixture is then cooled and 103 granisof the new product, a light yellow crystal` linews'olid,,are4 recovered by filtration. 33 grams of the product remain in solution and may be re-I covered,ifV desired,v` in any suitable mannen The melting point is about 103` C., which may be raised to -112 C. by recrystallizihg the compound from any suitable solvent such as toluene. Analysis: found S, 23.4%; N, 9.7%. Calculated OI C14H12N2S22 S, 23.5%; N,'10.2%.

Example D.-Reaction product of para-xylidine, formaldehyde, and mercaptobenzothiazole having the probable formula 12.1 grams of para xylidine (0.1 mol.) are dissolved in about cc. of alcohol, and 16.7 grams (0.1 mol.) of mercaptobenzothiazole are added. The mixture is thoroughly agitated, and an amount of formaldehyde solution of about 38% strength containing 3 grams (0.1 mol.) of formaldehyde is added. To hasten -the reaction the temperature is raised to about 30 C. When substantially all of the me'rcaptobenzothiazole has reacted with the p-xylidine and-formaldehyde, the resulting product, after a short time, begins to separate from the solution as a white, crystalline solid. When the crystallization is complete the reaction product is recovered in any suitable manner. It melts at about 119-120 C. The yield thus obtained is 27.5 grams V(theoretical yield 30 grams). An additional amount of the product may be recovered from the mother liquor by any suitable means.

The method of carrying out the process in the presence of a suitable organic solvent, as illustrated in Examples A, B, C, and D, is generally applicable to the preparation of the new compounds by the reaction of formaldehyde and mercaptobenzothiazoles with any primary aromatic amine. It is preferable to employ as the reaction medium an organic Vsolvent in which the reaction `product is not too soluble. For this purpose, a1- cohol, benzene, toluene, and xylene are suitable. In the case of the reaction using 2,5-dichloro aniline or alpha naphthylamine it is more desirable to employ benzene, toluene, or xylene, xylene being preferable on account of the lesser solubility of the products therein and the correspondingly greater ease of recovery of-the products.

Other modifications of the process may be employed as illustrated in the following examples:

Example E.-It has been found that a. product identical with that of Example C may be prepared in the following manner:

93 grams of aniline, 167 grams of mercaptobenzothiazole and 80 cc. of 40% formaldehyde solution are mixed in a Vessel with a powerful stirring apparatus, and heated to about 80 C. The contents of the vessel become fluid for a time, and as the reaction proceeds, gradually harden to a light buff homogeneous mass having melting point of lll-112 C.

Example F.-The same product may also be prepared in the following method:

grams of anhydro-formaldehyde aniline, prepared by the reaction between formaldehyde and aniline in known manner, and 167 grams of mercaptobenzothiazole are melted together with stirring. On heating for a. time at about 80 C.,

the whole mass sets to a homogeneous solid'melttions with such bases as aniline, o-toluidine and other fluid or low melting bases. The method illustrated by the process of Examples F and G is applicable in the case of those primary aromatic amines which are capable of forming with formaldehyde the corresponding isolable tertiary methylene'bases. Examples of such amines are aniline, o-toluidine, p-toluidine, p-xyldine, panisidine, p-chloro-aniline, andbeta naphthylamine, all of which may be made to yield the new compounds when treated according to the processes of Examples F or G, as well as by the methods of the other examples.

Examples of products which fall within the scope of the invention are shown in the following table:

Reaction product of- Color M01-ung pomt Mercaptobenzothiazole formaldehyde Bull 111-112 and aniline. Y

Mereaptobenzothiazole formaldehyde -..do 146 and o-toluidine.

Mercaptobenzothiazole formaldehyde do 11G-lll and p-toluidine.

Mercaptobenzothiazole formaldehyde .do

and p-xylidine.

Mercaptobenzothiazole formaldehyde do 156 and o-chlor anline.

'Mercaptobenzothazole formaldehyde .-.do 125 and alpha naphthylamiue.

Mercaptobenzothiazole formaldehyde ,do ll-162 and p-chlor aniline.

4-chloro mercaptobenzothiazole formal- Y ello wis h 120 dehyde and aniline. white.

Mercaptobenzothiazole formaldehyde Light bull.. 138

and B-naphthylamine.

4nitro mercaptobenzothiazole formalde- Ye ll o w is h 134 hyde and o-toluidine. orange.

4-nitro mercaptobenzothiazole formal- G r e e ni s h 115 dehyde and b-naphthlyamine. brown.

4-nitro mercaptobenzothiazole formal- R e d d is h llo-120 dehyde and aniline. orange.

Mercaptobenzothiazole formaldehyde White 98 and p-anisidine.

Mercaptobenzothiazole formaldehyde Buff 172 and 2-5 diehlor aniline.

Y Para-formaldehyde or other polymeric forms of formaldehyde may be used in the process of the invention in place of formaldehyde.

The moderate temperatures employed in the processes of the invention cause the reactions to take place without the elimination of any sulphur-containing substances such as hydrogen sulphide; water is eliminated during the condensation of formaldehyde with the amine. All of the reaction products which fall within the scope of the invention are denite crystalline compounds. The lability of the hydrogen atom of the mercapto group contained in mercaptothiazoles is well known, as is the tendency of such unsaturated groups as the C=N group, present in methylene aryl-imides, to become saturated by the opening up of the double bond and the addition thereto of ltwo monovalent elements or groups, especially when one of the said elements or groups available'is a labile hydrogen atom. Accordingly, the reactions of the present process are considered to proceed by the addition of the mercaptothiazole to the C=N group of a methylene aryl-imide, the methylene layleimide (or tertiary methylene base) being present either by direct addition to the reaction 'mixture as in Examples F and G, or by reason of its momentary `formation insitu in the reaction mixture as in *tion for the reaction in the" following-manner.: j

wherein R and R1 are as defined above. The dotted lines indicate the respective points of at- ;tachment of theH atom and of the Rr-S- ngrouping to the C=N group. The equation also shows that the reaction takes place without the elimination of any simpler sulphur-containing substances All of the elements of the methylene imide andof the mercaptothiazole are selenlto be present in the molecule of the nal product. It will also be noted that the trivalent nitrogen atom contained in the methylene aryl-imide remains trivalent in `the reaction product.

In view of the preceding, it will be apparent that the `formation of the reactionipro'ducts of this invention involve no liberation Ain. any form of the sulphur of the thiazole, that no'hydrogen `sulphide is formed, and'that therefore the resulting reaction products retain the originaly ysulphur content of the thiazole that is reacted upon,

In View of the fact that the polymeric forms of methylene aryl-imides behave chemically as if they were the simple `monomers having the formula R-N=CH2, it is obvious that the polymeric forms of said bases are equivalent tothe corresponding monomers for the purposesoflthis invention, and it is to be'understood that the lexpression methylene aryl-imide as used l'in the claims includes both the monomeric and the polymeric forms of said bases. By monomeric is meant the simple monomers having the formula R-N=CH2, and by polymeric is meant the polymers of the said simple monomers. The compounds as new chemicals are not'to be restricted to lthe particular methods of preparing them as set forth in' detail above, andthe claims are to Lbe construed as covering the compounds as new chemicals, however prepared.-

One use of the new compounds is as accelerators in the vulcanization of rubber.

With the detailed description given above, it will be obvious that modications will suggest themselves without departing from the ,principle of the invention, and it isnot desiredtoflimit the invention otherwise than as set forth Vin the appended claims. `I i i i i f3" Having thusl described my invention, what I claim and desire to protect by- LettersPatent is l. As a chemical compound-'the product of rey action of a mercaptobenzothiazle, formaldehyde vand a primary aromatic amine chosen from the benzene and naphthalene series, said compound retaining the original sulphur content of the thiazole reacted upon and having the probable general/formula Ri-S-CHQ--NH-#R where R' is an aryl group chosen l from the benzene vand naphthalene series and R1 is a benzothiazyl group.

2f 'As -a 'chemical compound the product of reaction of a mercaptobenzothiazole, formaldehyde anda primary aromatic amine chosen from the benzene and naphthaleneseries, having the probablegeneral formula R1`SCH2NH-R where R is` an aryl group 'chosen from the-benzene and naphthalene series and R1 is a benzothiazyl group said compound retaining the original sulphur content of thethiazole reacted upon.

3. A's a chemical compound the-product of reaction of Va mercaptobenzothiazole, formaldehyde `and aniline,` having the probable general formula R1-S-CHz-NH-C6H5 wherein R1 is a benzothiazyl group said compound `retaining the original sulphur content of the thiazole reacted upon.

4. As a chemical compound the product of reaction of a mercaptobenz'othiazole, formaldehyde,

and a, toluidine, -having the probableformula Rl-S-'CHz-NHfCsHiQCHs wherein R1 is a benzothiazyl group saidcompound retaining the original sulphur contentof the thiazole reacted up0n i A Y 1' `5. A compound having `the probable general formula R1-S-CH2y--NH-R wherein R is an aryl group chosen from `the benzene and nephthalene' serieswand "R1 is a benzothiazyl group, which compound is a crystalline solid, soluble in alcohol and inbenzol. l i

6. As a chemical compound the reaction prod- -uctof mercaptobenzothiazole,` formaldehyde, and janiline, having the probable formula Y /1`\ f \o-s.cn.--NH

andmelting at about 110"-112QC`. after recrystalliz'ation froml toluene said compound retaining the original sulphur content of thelthiazole reacted upon. A l

'7.4l As a chemical compound the product of re- `action of mercaptobenzothiazole, formaldehyde,

and a toluidine having the probable formula said compound retaining the original sulphur content of the .thiazole reacted upon. f

, `8. As a chemical compound the product of reaction ofV` mercaptobenzothiazole, formaldehyde, and o-toluidine, havingthe probableformula \c-soH2-NH-cng and melting at about' 111 C.lafter.recrysta.lliza tion from alcohol said compound retaining the original sulphur content of the thiazole reacted upon. 4

10. A process of producing a methylene arylamino derivative of a mercapto-benzothiazole which comprises reacting a mercapto-benzothiazole, formaldehyde and a primary` aromatic amine chosen from the benzene and naphthalene series at a temperature suciently moderate t cause no elimination of hydrogen sulphide from the reaction mixture, whereby the resulting product retains. the originall lsulphur content of the mercapto-benzothiazole reacted upon.

11.AV processof producing a methylene arylamino derivativez of 4mercapto-lcenzothiazole which comprises reacting` mercapto-benzothiazole, formaldehyde and aprimary aromatic amine chosen from the benzeneand'naphthalene series at a temperature sucientlymoderate to cause lno .elirninationro hydrogen sulphide from the reaction-mixture, whereby kthe resulting product retains the original sulphur .contentof the mercapto-,benzothiazole reactedupon.- f

12. In Jthe process ot producing v a reaction product `of a mercaptoarylthiazole vof the benzene series, formaldehyde, and a primary aromatic amine, the steps which include reacting formaldehyde with `a primary aromatic amine chosen from the benzene` andl naphthalene series capable of forming therewith an isolable tertiary methylene base to form such tertiary methylene base, and reacting such base with a mercaptoarylthiazole of the benzene series at temperatures not in excess of:a.l;out 80o C. 13.. In thefprocess of producing a reaction product of `a mercaptobenzothiazole, formaldehyde, and a primary aromatic amine, the steps which include reacting formaldehyde with a primary aromatic amine chosen from the benzene and naphthalene series capable of forming therewith an isolable tertiarynmethylene Vbase to form such tertiaryY methylene base, and reacting such base with a mercaptobenzothiazole at ternperatures not V:ln excess of about 80 C. y

14. In the process of producing a reaction product of a mercaptcbenzothiazole, formaldehyde, and a primary aromatic amine, the steps which include reacting formaldehyderwi'th a primary aromatic amine chosen from the benzene and naphthalene series capable of forming therewith an` isolable tertiary methylene base to form such tertiary methylene base, and reacting such base with mercaptobenzothiazole at temperatures not in excess of about 80" C. n

l5. The process of producing an arylaminomethylthiazyl sulphide which comprises effecting a reaction at Vtemperatures not in excess of about '80I C. between a mercaptoarylthiazole of the benzene series and an arylmethylene-imide having the aryl portion chosen from: the benzene and naphthalene series.

16. The process of producing an arylaminomethyl thiazyl sulphide which comprises effecting"'a"--reac tion at temperatures not in excess of about V8O" C; between a mercaptobenzotl'iiazole andan arylmethylene-'imidehaving the aryl portion chosen from the benzene and naphthalene series. 'A 1 17. The process accordingto claim 16 wherein the arylrnethylene-im'ide is preformed.

18. The process according to claim 16 wherein the arylmethylene-imide is formed in situ in the presence of a mercapto-benzothiazole.

19. A methylene arylamino derivative of a mercaptobenzothiazole havingthe general formula `.""1

where AR is an arylene group of the benzene series, and R is a methylene arylamino group having the aryl portion chosen from the benzene and naphthalene series.

20. A compound having the general formula ,\C-S-R in which R consists of an arylamino group having the aryl portion chosen fromV the benzene and naphthalene series and a methylene radical whose carbon atom is joined to the amino nitrogen of said arylamino group.

21. A compound having the general formula /Ns AR /Ns AR C-S-R where AR is an arylene group of the benzene series and R is a methylene tolylamino group.

24. A methylene arylamino derivative of mercapto-benzothiazole having the general formula where R is a methylene phenylamino group, and having a melting point of about 110-112 C. after re-crystallization from toluene.

2,5. A methylene arylamino derivative of mercapto-benzothiazole having the general formula Where R is a methylene o-tolylamino group and having a melting point of about 145 to 146 C. after re-crystallization from alcohol.

26. A methylene arylamino derivative of mercapto-benzothiazole having -the general formula Where R is a methylene p-tolylamino group, and having a melting point of about 111 C. after re-crystallization from alcohol.

. CLYDE COLEMAN. 

